Following operation for duodenal ulcer disease, reflux of bile into the stomach and gastritis is a common endoscopic finding. Most patients are asymptomatic. In other patients, pain, bile vomiting, hypochlorhydria, and diffuse gastritis is present - post-operative alkaline reflux gastritis. This study is proposed to determine if there are significant alterations in the composition of bile which results in mucosal damage and symptoms. Twenty patients will be studied in a retrospective manner. Ten patients following vagotomy and Billroth II for duodenal ulcer performed at least six months previously are selected for symptoms and findings characteristic of alkaline reflux gastritis. All patients must have pain, gastric hypochlorhydria, and endoscopic and microscopic evidence of diffuse gastritis. Ten patients will be selected who have no post-operative complaint but have had a vagotomy and Billroth II for duodenal ulcer. These latter ten patients will serve as controls. All patients will have endoscopic examination of the stomach with biopsies near the stomal area. At the time of endoscopy, a sample of bile is aspirated from the stomach and total bile acid concentration by the enzyme method and percent composition of the individual bile acids by gas-liquid chromatography are determined. From preliminary studies a statistically significant increase in deoxycholic acid has been present in the symptomatic patients compared to those without symptoms. This alteration in bile acid composition may be the significant factor which determines the development of reflux alkaline gastritis following operation for duodenal ulcer. This preliminary investigation requires additional cases to confirm this finding. Also, patients undergoing operation for duodenal ulcer will have bile samples collected before or at the time of operation and periodic samples collected post-operatively. Qualitative and quantitative bile acid analysis will be performed and compared to the clinical course of each patient. Correlation between the development of reflux alkaline gastritis and alterations in the composition of bile with an increase in deoxycholic acid are expected.